Apparatuses and methods related to a high pressure fluid processing device having a dual check valve setup that can be quickly and easily maintained with replacement parts are disclosed herein. In a general example embodiment, a high pressure processing device includes a body including a first surface having a first recess, a second surface having a second recess, and a third surface having a third recess, a first subassembly at least partially inserted into the first recess of the body, the first subassembly including a first check valve, a second subassembly at least partially inserted into the second recess of the body, the second subassembly including a second check valve, and a third subassembly at least partially inserted into the third recess of the body, the third subassembly coupling the body to a fluid driving mechanism, wherein the first subassembly, second subassembly and third subassembly are configured to be independently attachable to and detachable from from the first recess, second recess and third recess, respectively.